1. Field of the Invention
The invention relates to an arrangement for bridging expansion joints in carriageways, especially bridges, having one or more parallel plates which run at right-angles to the direction of the carriageway, are adjacent at the top to the surface of the carriageway and are supported at the bottom on bars which run at right-angles to the expansion joint and transmit loads directly or indirectly into the edges of the carriageway adjacent thereto, and wherein a device for controlling the spacing of the plates is provided.
2. Description of the Prior Art
In known arrangements of that type (for example German patent specifications Nos. 16 58 611 and 30 19 594), it is necessary to control the spacings between the plates in conformity with the width, in each case, of the expansion joints and also as a reaction to the braking and traction forces of vehicles passing over.
Numerous control devices are known which bring about the control of the plates in such a manner that these uniformly divide the joint gap by using different means such as articulated levers, scissor rods, toothed racks, elastic control parts or the like.
The known lever controls (for example German Offenlegungsschrift No. 24 21 964) do not have any shock-absorbing action; in time their joints deflect.
The known elastic control devices (for example German patent specifications Nos. 16 58 611 and 30 19 594) are less accurate than the lever controls mentioned, their inaccuracy increasing as the deflecting forces decrease and as the rubber control parts age.